Heat-tbansfeb system fob aircraft



H. F. PARKER HEAT TRANSFER SYSTEM FOR AIRCRAFT Original Fil'eci April 28. 1922 INVENTOR I K QWW ATTORNEY Rei ue'd May31, 1927. I

UNITED STATES PATIENT OFFICE.

EUHPHREY I. OI P HILADELI PHIA, PENNSYLVANIA.

HEAT-TRANSFER SYSTEM FOR AIRCRAFT.

Original No. 1,503,374, dated'I uly 29, 1924, Serial K0. 557,229, filed April 28, 1922. Application for v reissue fledllarchlfl, 1926. Serial No. 93,765.

This invention relates to a heat-transfer system for aircraft, and-has forits objectthe improvement of processes dependent on the dissipation of the waste heat from the hydrocarbon motors; and particularly to the recovery of water fromthe exhaust of such motors to replace weight of the fuel burned and thus maintain the total weight of the ship; and in lighter than air craft the utilizationof the heat of the motor exhaust for buoyancy control; and for other purposes whereby the transfer of heat is desirable.

The invention seeks mainly to provide a "cry simple and eilicient means and method for recovery of sufiicientwater from the engine exhaust tocompensate for the loss of weight due to the consumption of fuel, the said means being of such novel construction and arrangement as to offer a negligible amount of additional head resistance in flight. Furthermore, the invention provides a construction which additionally permits,

by an extremely simple method, the utilization of waste heat to obtain a substantial degree of buoyancy control.

The invention primarily is an improved means of dissipating heat, the improvement lying in the utilization of external surfaces already existing on the aircraft instead of providing additional means located in the air stream, and which are objectionable be' cause of the head resistance thus offered to the flight of the ship. The primary requirement for heat transfer is a surface which separatesthe hot'fiuid from the cold fluid, and through which the heat is transferred. The quantity ofheat transferred is depend ent on the area of the surface and on the velocities of the fluids, in addition to other factors, such as the temperature difference between the hot and cold fluids and their viscosities and specific heats, Furthermore it is dependent on the friction between the fluids and the surface. Now in all aircraft there are large areas of surface oflering frictional' resistance to the air through which the craft passes. A particular example of this is the outer envelope of the airship. In such case there is a surface which is a necessary source of resistance, but is capable of transferring heat; on one side of that surface a cold fluid flows (the air), at high velocity and with considerable skin friction. If now, a hot fluid (e. g. engine exhaust) be caused to How on the other sideof thesun face,.1n contact with the surface,-heat will flow from the hot fluid, through the wall, to a the cold fluid on the other side of the wall. Aisit is necessary to conserve the fiuidsit is desired to cool, the space through which they move must be limited. To effect this a pas-- sage is created, one wall of the passageway being thesurfa'ce exposed to the air stream,

and the other Wall an idle surface placed inside the structure of the aircraft.

Other-objects of this invention, not here more particularly enumerated, will be clearly understood from the following detailed description of the same.

The invention is clearly illustrated in the accompanying drawings, in which Figure 1 is a fragmentary side elevation of an aircraft showing the novel heat transfer means and associated devices connected therewith; Figure 2 is a detail fragmentary horizontal section taken on line 22.in said Figure 1; and Figure 3 is a. fragmentary transverse section taken on line 3-3 in Figure 1, said view being drawn on an enlarged scale. a

Similar characters of reference are employed in all of the hereinab'ove described views to indicate corresponding parts.

Referring .now to the said drawings, the lifting gas supporting the air ship is contained in the gas cell 4; the reference character 5 indicates the longitudinal structural members forming part of a frame of a rigid air-ship rand 6 indicates the outer envelope of the air-ship.

The products 'of combustion are discharged from an engine or hydrocarbon motor (not shown) through the exhaust pipe 7 into the passageway 8. The outer surface of this passageway is formed in the main by a portion ,of the outer fabric covering or envelope 6 of the hull of the air-ship, as at 9,

but that portion thereof nearest the entrance surface utilized as the outer wall of the pasl0 sage 8 where suchportion of the fabric is reasonably remote from the point .of en-,

trance of the hot gas of the exhaust. If desired metallic surface may be used throughout the area employed as the outer wall of the passage 8, the same having greater durability, but the use of fabric for the cooler portions or outlying areas enables a saving in weight to be made. The inner wall 8 of the passage 8 is preferably of sheet metal construction.

The direction of flow of the outer air stream is, of course. horizontally rearwards. The direction of flow of the hot exhaust gases to be cooled -is determined by two fac tors. First, it is desirable when possible to have air and exhaust gases in counter flow, that is respectively moving in opposite directions, as this arrangement gives the most effective cooling for a given area of surface and velocity of flow. In the later stages of the cooling, however, it is advantageous to cause the hot gases to flow upwards. Water commences to condense from exhaust at about 125 Fahrenheit and the condensation continues until the gases are finally discharged at about 85 Fahrenheit. In a sim-.

ple counter-flow system this water will drain off at a temperature below 100 Fahrenheit.

By arranging the cooling surface so that the coolest portion is at the top, the water as it condenses, will run down over the hotter surface; It is desirable to drain it off before it reaches a point where it would be turned to steam. A two-fold advantage is then obtained. Firstlyfsome of the heat that would have to be given up to the air The water as condenses flows down the inner side of the fabric wall 9 until it en-- counters the catch basin or trough 12, which is preferably connected with the upper margin of the plate 10, to project into thev passage 8, said catch basin or trough collecting the water and delivering-the same to a pipe 13 which leads to ballast storage tanks (not shown). Before final discharge, the exhaust, gases may be passed thru a separator 14 to remove particles of water which-happen to be carried along in suspension in the gas stream.. An' apparatus similar to that i used in humidifying and dehumidifying in air conditioning work is suitable for the pursurfaces 9 and 10, some of it is given up to the air in the annular space 17 which is disposed between the gas cells 4 and the outer envelope 6. It is in the method of dealing with this portion of the heatlliat a measure of buoyancy control for the aircraft may be effected. i

The hull of the ship is provided with an air intake port 18, provided with a suitable closure means 19, at a point forward of the heat transfer system, throughwhich air may be admitted to the annular space 17 ,and in addition the hull of the ship is also provided with a second air intake port-20, also provided with a suitable closure means 21, located im. ediately to the rear of said heat transfer system. The hull of the ship is also provided. with an air discharge port 22, having suitable controlling means 23, which is located to the rear of the heat transfer sys tem and spaced away from the same and the intake port 20 as may be found expedient.

If it is desired to effect a'conclition making for' a greater lift of the aircraft, the forward air intake port 18 may be clos d, stopping the entry of cold air into the annular space 17. The heat given up by the inner wall 8 of the passage 8 is now retained by. the air in the annular space 17 expanding such air and rendering it more buoyant. In addition to this the intake port 20 situated immediately to the rear of the heat transfer system may be opened causing the air which has passed by the outer hot surface of the metal plate 10 to be carried into theannular space 17 thus further adding heat to expand theair therein and increase the buoyancy of the craft. This buoyant heated air in turn heats the lifting gas in the containers which is another factor in producing greater lift since the lifting-gas expands, while the ex-v pansion of the air. in the annular space 17 causes the expulsion of some of the cold air formerly there and addsto the increased lifting efl'ect. When the temperature of the gas in the containers or cells t and the air, 1n the annular space 17 is lowered the converse eflect may be attained. In this case the intake port 18 is open so that the air entering therethrough from the atmosphere sweeps out the warm air in the annular space around the heat transfer system by discharging. the same through the discharge port 22, the intake port 20 being under such circumstances closed, all of which tends to reduce the temperature of the'air in the annular space 17, consequently also cooling the gas contalners or cells 4 and the lifting gas,

causing a contraction of the latter. In this manner the lift of the ship may be reduced without valving lifting gas.

So far as the heat transfer means per se is concerned I do not limit the employment of the novel arrangement and construction above described to the purposes of water recovery or buoyancy control above discussed, for I also conceive my invention to broadly include the utilization of an "extcrior wall surface of an aircraft incombination with a heat transfer means or system, to serve as the main rediating surface of the latter.

I am aware .that changes may be made in the arrangements and combinations of the various devices and parts making up the present invention, as well as in the details of the construction of the same, without departing from the scope of my invention as set forth in the foregoing specification, and

as defined in the appended claims. Hence, I do not limit my invention to the exact arrangements and combinations of the several devices and parts as described in the said specification, nor do I confine myself to the exact details of the construction of the said parts as illustrated in the accompanying drawings.

I claim:

1. The combination with an airship provided with an outer envelope and lifting gas containers within and spaced from said outer envelope of heat transfer means comprising an enclosed passage the outer wall of which is aligned in the plane of said 'outer envelope, an adjustable port forward of said heat transfer means for directing air into the space between said outer envelope and gas containers, and an adjustable port to the rear of said heat transfer means for directing air into saidspace and from said space to the atmosphere.

2. The combination with a surface of an airship exposed to the air stream, of a heat transfer means comprising a conduit the main heat exchanging wall of which is formed by a portion of said exterior surface, means for delivering engine exhaust gases into said conduit, and means for collecting the water condensed in said conduit.

3. The combination with an airship provided with an outer envelope and internal lifting gas containers separated from said envelope by an annular space, of heat transfer means comprising an enclosed. passage the outer wall of which is formed by a portion of said outer envelope, means for delivering engine exhaust gases into said passage, and means for collecting the water condensed in said ass'age.

4. The combination with an airship pro-' vided with an outer envelope-and internal lifting gas containers separated from said envelope by an annular space, of heat transfer means comprising an enclosed passage the outer wall of which is formed by a portion of said outer envelope, an intake port provided in said envelope forward of said heat transfer means, meansfor opening and 4 fer means comprising an enclosed passage the outer wall of which is formed by a portion of said outer envelope, and means provided insaid outer envelope ad acent to said heat transfer means for admitting air into said annular space.

6. A method of water recovery for'ballastlng alrcraft CODSISlIIDg'IH passing engine exhaust gases isolated from. the sustaming gas against the inner surface of an exterior wall of said aircraft the outer surface of said exterior wall being exposed to theair stream, whereby Water is condensed from said exhaust gases on said inner surface, and then collecting said condensation for delivery to ballast tanks.

7. A method of recovering water on aircraft consisting in passing engine exhaust gases isolated from the sustaining gas against the inner surface of a fabric Wall, the outer surface of said Wall being exposed to the air stream, whereby water is condensed from said exhaust gases.

8. In an airship, apparatus for recovering Water from the exhaust gases from the motors comprising a conduit exposed in-part to the air-stream through which said exhaust gases are passed, the exposed portion of said conduit being divided into two zones, the first zone comprising that area of said V ce exposed portion which is subjected to comparatively high temperatures, and the second zone comprising that area which is subjected to a temperature-less than the boiling point of water.

9. An apparatus for recovering water from the exhaust gases from airship motors comprising a conduit exposed in part to the air-stream, the exposed portion of said conduit being divided into two zones, the first zone nearest to the entrance of said exhaust gases being of a material adapted to resist high temperatures and the second zone being adapted to drain the water condensed.

10. The combination with the surface of an aircraft exposed to the airstream, of heat transfer means comprisin a conduit provided with a heat exchanging wall which is formedcby' a portion of said surface, means for. delivering gas comprising Water in a' gaseous, state into said conduit, and means for collecting the water condensed in said conduit.

11. In an' aircraft provided with a fuel.

gaseous state, and means for collecting the Water condensed in said conduit.

12. A method of condensing water vapor on aircraft consisting in passing Water con taining gas created as a. result of the combustion of fuel, and isolated from the sustaining gas, against the inner surface of a fabricwall, the outer surface of said wall being exposed to the airstream.

13. In an airship, apparatus for recovering water from the exhaust gases from the motors, comprising a conduit thru which said exhaust. gases are passed, said conduit being exposed in partto the airstr'eam and being divided into two zones, the first zone comprising that portion of the conduit wherein the gases are at a temperature in excess of the boiling point of water, and the second zone comprising that portion in which said gases are at a temperature below.

the boiling point. of Water.

14. The method of recovering-in a condensed state the aqueous constituent of the exhaust gases of an aircraft engine, which comprises exposing said gases, while isolated from the sustaining gas, to the airstneam thru the medium of a heat conducting area.

of the Wall of the craft of dimensions suificient to permit the transfer of heat from said gases to said airstream t0 eflect condensation of the said aqueous constituent, and

- permitting the resulting water of condensation to flow to a receptacle located within the aircraft.

15. In an aircraft, a heat engine, and means for recovering the aqueous constituent of gases produced by Waste heat of said engine comprising a conduit leading from the source of said gases thence to a specification.

condensing chamber located within, the -en-. velope and separated from the airstreamby,

a wall composed in part of the envelope-of to a; receptacle located vided with an outer-envelope and lifting gas containers within-amtspaced from said outer envelope of heat transfer means comprising an enclosed passage the outer wall; of which is aligned 111 the plane of 5211(1 outer envelope, an'a-djustable poi-t forward of said heat transfer means for directing airinto the space between said heat transfer means and gas containers, and an adjust' ableport to the rear of said heat transfcr means for directing air into said-space and from said space to the atmosphere;

17. In combination with the fabric surface of an airship'cxposed to the air stream,

of heat transfer means comprising a fabric.

conduit the main heat exchange wall or which is famed by a portion of said surface. means for delivering engine exhaust gases into said conduit and means for collecting the water condensed in said conduit.

18. In an airship, means for iecovering water from the exhaust gases from the engine, comprisi.ng a fabric conduit an area of the outer surface of which is exposed to the air stream, said conduit being in communi cation with the source of-said exhaust gases, and means for collecting condensed Water from said conduit.

19. In an airship, means for condensing Water. vapor from gas created as a result of the combustion of fuel, comprising a fabric conduit an area of the outer surface of which is exposed to the air stream, said conduit being in communication with the source of said gas, and means for collecting condensed water from said conduit.

20. In an airship, means for condensing Water vapor comprising a fabric conduitan area of the outer surface of which is exposed to the air stream, said conduit being in communieation with the source of said vapor and means for collecting condensed Water from said conduit.

In testimony'whereof, have signed this HUMPHREY F. PARKER. 

